Asiobaccha aea Mengual & Thompson

Mengual, Ximo, 2016, A taxonomic revision of the genus Asiobaccha Violovitsh (Diptera: Syrphidae), Journal of Natural History 50, pp. 2585-2645 : 2590-2592

Asiobaccha aea Mengual & Thompson sp. nov.

( Figure 3a, b, e )

Description

Male: Head. Face with distinct round facial tubercle, yellow with some brown lateral areas, black pilose, white-silver pollinose laterally and shiny (bare) medially on tubercle; gena yellow-brown ( Figure 3e ); lunule dark, yellow basally; frons slightly protruded forward, black, black pilose, brown pollinose laterally and dorsally, shiny basomedially; vertical triangle narrow, black; antenna yellow, black pilose; arista brown, bare; eye bare; occiput black, white-silver pollinose, yellow pilose on ventral 3/4 and dark pilose on dorsal 1/4.

Thorax. Scutum black, dark pilose, brown pollinose; mesonotal fringe well defined on anterior part of scutum, with yellow-golden pile; postpronotum black, bare, brown pollinose; postalar callus lighter, tawny; scutellum yellow (tawny), brown pilose, subscutellar fringe absent ( Figure 3a, b ). Pleuron black, except posterior anepisternum lighter posteriorly as well as katepisternum dorsally and anepimeron, yellow-brown (tawny) pilose, anterior anepisternum with pile on anterodorsal quarter; densely golden pollinose on lighter areas; metaepisternum pilose ventrad to spiracle; metasternum bare; calypter small, reduced, yellow; plumula almost absent, pale; halter pedicel yellow, capitulum dark; posterior spiracular fringes yellow. Wing: entirely microtrichose except posterior margin of alula bare, mostly infuscated, brown with apical margin (beyond vein M2) hyaline. Legs: pro- and mesoleg entirely yellow except dark coxae; metaleg with dark coxae and trochanter; yellow metafemur with an almost imperceptible brown annulus; metatibia dark brown, lighter basally; metatarsus pale (white-yellow), except metabasitarsomere black on basal 2/3 or more.

Abdomen. Petiolate, unmargined, mostly black pilose. Tergum 1 black, yellow pilose laterally; tergum 2 tawny, yellowish, darker on posterior 1/4 – 1/5; tergum 3 black with two lateral, square yellow maculae on anterior half of the tergum, reaching anterior and lateral margins; terga 4 and 5 entirely black ( Figure 3a, b ). Sterna 1 and 2 yellow; sternum 3 yellow on anterior 1/2, black on posterior 1/2; the remainder of sterna black.

Female. Similar to male except for normal sexual dimorphism and as follows: face yellow pilose ventrally, frons grey pollinose, and scutellum yellow pilose.

Length (N = 1). Body, 15.1 mm; wing, 12.5 mm.

Geographical distribution

Species known from Solomon Islands.

Etymology

The name aea is an arbitrary combination of letters and is to be treated as feminine.

Differential diagnosis

Species with a mesonotal fringe well developed, broad alula and wing entirely microtrichose, which is dark brown even basally with hyaline apical tip. This new species is similar in overall appearance to A. bicolor or A. loriae , but A. aea has an entire microtrichose wing and a mesonotal collar. It can be distinguished from A. nubilipennis and morphologically close species by the wing microtrichia.

Type locality

Solomon Islands: Malaita Province, Malaita Island, Su ’ u, 9°04 ’ 47 ’’ S, 161°09 ’ 58 ’’ E .

Material examined

Type material. Holotype, male, deposited in the Canadian National Collection (Ottawa, Canada) and labelled: ‘ Solomon Islands // Malaita Is // Su’ u // 16.viii.19 34 // H.T.Pagden ’ [green] ‘ Frank M.Hull // Collection // C.N.C.1981 ’, ‘ HOLOTYPE // Asiobaccha // aea // des. X. Mengual 2014’ [red] (specimen photographed). Paratypes: SOLOMON ISLANDS: Guadalcanal Prov., Honiara, December 1975, N.L.H. Krauss [1♀, BPBM]; Guadalcanal Prov., Tenaru R, January 1945, G.E. Bohart [1♀, USNM, USNMENT 00890778].

Remarks

The female specimen in the USNM was identified as Episyrphus 74–28 Thompson, in litt.

Figures

Figure 3. Asiobaccha aea Mengual & Thompson sp. nov. a–b, e, holotype ♂. (a) Dorsal view; (b) lateral view; (e) frontal view. Asiobaccha albipeza Mengual sp. nov. c–d, f, holotype ♂. (c) Dorsal view; (d) lateral view; (f) frontal view. Scale bars: a–d = 2 mm; e, f = 1 mm.